diff --git a/src/elli/solver.py b/src/elli/solver.py
index e0e8d48a..4f3ada49 100644
--- a/src/elli/solver.py
+++ b/src/elli/solver.py
@@ -26,8 +26,11 @@ class Solver(ABC):
     def calculate(self) -> Result:
         pass
 
-    def __init__(self, experiment: "Experiment") -> None:
-        self.experiment = deepcopy(experiment)
+    def __init__(self, experiment: "Experiment", save_experiment: bool = False) -> None:
+        if save_experiment:
+            self.experiment = deepcopy(experiment)
+        else:
+            self.experiment = experiment
         self.structure = self.experiment.structure
         self.lbda = self.experiment.lbda
         self.theta_i = self.experiment.theta_i
diff --git a/src/elli/solver4x4.py b/src/elli/solver4x4.py
index 6c3a10cd..8f57e22a 100644
--- a/src/elli/solver4x4.py
+++ b/src/elli/solver4x4.py
@@ -314,9 +314,12 @@ def get_k_z(
         return sqrt(k_z2)
 
     def __init__(
-        self, experiment: "Experiment", propagator: Propagator = PropagatorExpm()
+        self,
+        experiment: "Experiment",
+        propagator: Propagator = PropagatorExpm(),
+        save_experiment: bool = False,
     ) -> None:
-        super().__init__(experiment)
+        super().__init__(experiment, save_experiment)
         self.propagator = propagator
 
     def calculate(self) -> Result: